Calcium Supply Research Articles

Актуальные вопросы нутрициологии в акушерстве: роль кальция и витамина D в формировании благоприятных условий для вынашивания плода

Epidemiological studies show a high prevalence of vitamin D deficiency in women, including pregnants and lactating mothers. Adequate supply of calcium and vitamin D is of paramount importance for the prevention of the gestation course disorders, perinatal complications and development of a number of diseases in a child. Preconceptional preparation and long-term intake of calcium and vitamin D are also necessary in high&risk pregnant groups, most sensitive to impaired adequate calcium intake. For this purpose, it is feasible to use modern vitamin&mineral complexes containing calcium and vitamin D in sufficient quantities.

Energy and nutrient supply according to food insecurity severity among Mexican households

Studies from Latin America have shown that food insecurity reduces dietary diversity. However, dietary diversity measures do not account for the energy and nutrient supply in households. The objective of our study was to know whether there are differences in food, energy and nutrients supplies in Mexican households according to their food insecurity level. We analyzed the database of the National Household Income and Expenditure Survey performed in Mexico in 2014. The modified Latin-American and Caribbean Food Security Scale was used to determine the existence of household food security or insecurity. Participants registered foods and beverages available at their homes during the previous week. The supply of energy and nutrients was estimated using Mexican and American food composition references. Mexican food secure households had greater supply of healthy (e.g., fresh fruits and vegetables, fish and seafood, and fresh meats) and unhealthy (e.g., processed meats, fries, sugar-sweetened beverages, desserts, and alcoholic beverages) foods. By contrast, food insecure households rely on cheap staple food (e.g. maize, rice, pulses, eggs, and sugar). There was a linear relationship between the energy density and severity of food insecurity. Households with mild and moderate food insecurity had greater total energy supplies than households with food security and severe food insecurity. Food insecure households had greater supplies of carbohydrates, cholesterol, iron, and magnesium, but lower supplies of protein, fat, vitamin C, vitamin A, potassium, calcium, and sodium. Most of the results suggest that food insecure households are exposed mostly to negative aspects of the nutrition transition because they have greater access to energy and lower availability of some micronutrients.

Effects of low phosphorus intake on serum calcium, phosphorus, alkaline phosphatase activity and parathyroid hormone in growing dogs.

A sufficient and balanced supply of calcium and phosphorus is important mainly for the skeletal health of dogs, especially during growth. Numerous reports and research results are quoted, which focus mainly on the effects of both deficient or excessive calcium supplies. The important role that phosphorus plays in the disruption to skeletal development is also explored. The aims of this study were to evaluate the effects of a low phosphorus supply on selected serum parameters of calcium and phosphorus metabolism in both medium and large breed growing dogs, alongside the effects on the apparent digestibility and retention of these minerals as well as the musculoskeletal development, which were published before. Beagle and Foxhound-crossbred puppies (n=53) between the age of 6 and 24weeks were either fed a balanced (control) or a low phosphorus diet, the latter one providing about one-third of P amount fed to the control group. In regular intervals, blood samples were obtained to measure serum levels of phosphorus, calcium, alkaline phosphatase activity (ALP) and parathyroid hormone (PTH). Functional Additive Mixed Models were used to analyse these serum concentrations per group and per diet. In the puppies being fed the low phosphorus diet, a distinct decline of serum phosphate concentration was detected with a more pronounced and prolonged effect in the smaller Beagles. At the same time, serum calcium concentration altered in the opposite direction, implying that the product of calcium multiplied by phosphorus was regulated more closely than the calcium to phosphorus ratio. The PTH concentrations were reduced and ALP activity increased at certain time points during the low phosphorus feeding compared to the puppies being fed the control diet. In the latter group, an effect of time or maturation could be demonstrated in relation to the serum phosphate concentration.

Influences of trace mineral nutrition and maternal flock age on broiler embryo bone development.

At hatch, the chick skeleton is a miniature of that of the adult bird. The hen deposits calcium, phosphorus, and trace minerals (copper, zinc, and manganese) along with vitamin D into the egg to allow development of the embryonic skeleton. The main source of calcium is the eggshell, whereas phosphorus, trace minerals, and vitamin D are mainly derived from the yolk. Calcium is absorbed from the eggshell and transferred to the embryo and yolk through the chorioallantoic membrane, whereas phosphorus and trace minerals are simultaneously mobilized by the yolk sac membrane. These processes start at day 12 of incubation and peak at around day 17. While the eggshell provides a steady supply of calcium until 19 d of incubation, phosphorus and trace mineral reserves decrease considerably and minimal skeletal development occurs in the last 3 d of incubation. Whether the low levels of phosphorus and trace minerals at late incubation prevent further bone growth, or some other biological control exists preventing further mineralization towards hatching is unknown. Maternal transfer of minerals and the influence of trace mineral form in the hen diet to advance the state of skeletal development at hatch have received increased research attention. Minimal effects on yolk mineral composition and bone growth were observed in the offspring of hens fed different forms of trace minerals. Embryos from young hens had inferior bone development towards the end of incubation and at hatch relative to chicks from older hens. This effect is likely a consequence of limited egg nutrient resources in eggs from young hens. The influence of maternal nutrient transfer on embryonic bone development has been clearly established. However, attempts to increase the state of skeletal development at hatch through increasing egg mineral content have met with limited success. The focus of this paper is the relationship between skeletal mineralization of the chicken embryo throughout incubation and egg mineral supply.

Effects of calcium supply on soybean plants

This paper aims to evaluate the effects that calcium application on leaves and flowers of soybean plants exerts on yield and yield components. Two experiments were carried out in the 2013/2014 crop season under field conditions. In the first experiment, two soybean cultivars – one of determinate growth habit (BMX Ativa) and another of indeterminate growth habit (BMX Alvo) – were submitted to calcium spraying with four nozzles (twin flat, twin flat fan, cone and hollow cone). In the second experiment, soybean plants (BMX Ativa cultivar) were sprayed with calcium on the leaves and flowers at R1 or R3 growth stages. Subsequently, the plants were maintained or not under a 50-percent shade protection during flowering stage. Calcium spraying on soybean leaves or flowers during the flowering stage did not increase pod set, number of seeds, or grain yield. The calcium content in soybean flowers is not affected by foliar application thereof.

Prevention of Flower Abortion and Leaf Damages in Anemone coronaria by Ca Supplements

Ca deficiencies induce a range of physiological disorders in plants. The disorders typically appear in young growing tissues that are characterized by high demand for Ca and restricted Ca supply due to low transpiration. In this study, we examined the effect of supplementing Ca by foliar spray and through the irrigation solution to Anemone coronaria plants, in order to evaluate if flower abortions and leaf damages that appear in the production fields are related to Ca deficiencies. With the goal to develop a preventive nutritional regime, four Ca treatments were evaluated. The supplemented Ca was applied with the fertigation solution in the concentrations of 60 or 110 ppm Ca; with the 60 ppm application an additional application of Ca by foliar application was tested in concentrations of 3 g/l Ca or 6 g/l Ca, as Ca(NO3)2. The plants were cultivated in a net-house, in soilless culture (Tuff) beds. Application of 110 ppm Ca compared to 60 ppm with the fertilizing solution increased the concentration of Ca in the leaf tissue, resulting in an increase in the quantity and quality of the flowers. Calcium supply by foliar spray, at both 3 g/l or 6 g/l Ca(NO3)2 caused leaf necrosis and did not improve yield production. Application of 110 ppm Ca reduced the concentrations of Mn, Cl and Na in the leaves. Application of Ca in the irrigation solution, or by foliar spray, did not reduce the percentage of non-marketable flowers. The identified lower concentrations of Ca in damaged compared to non-damaged leaves on the flower stem suggests that the damages to the flowers and the leaves is related to local deficiencies of Ca.

SUPPRESSING VITAMIN D AND CALCIUM IN PREGNANT WOMEN

The aim of this study was to evaluate the sufficiency of vitamin D and calcium intake for pregnant women according to the survey performed among pregnant women to determine their unfulfilled needs.Materials and methods. The survey was conducted among 60 pregnant women at 23-38 weeks of gestation, treated at the Ternopil municipal hospital No 2. The goal was to determine the amount and sources of vitamin D and calcium in the women’s body.Results. The average age of pregnant women was 23,4 ± 4,03 years, most of them (45,0%) had a higher education. Over half (51,7%) of the women under survey were first time mothers. Based on the women’s weekly diet, it has been found that the largest amount of vitamin D intake occurred with egg yolk (85,7 ± 18,1 IU), sea fish (65,1 ± 13,4 IU), animal products/meat (45,0 ± 2,1 IU). Calcium intake was predominant with meat (680,8 ± 8,2 mg) and dairy products: cottage cheese (153,3 ± 13,1 mg), milk (112,6 ± 11,3 mg) and hard cheese (102,1 ± 7,7 mg). The average daily intake of vitamin D with food was 324,7 ± 38,0 IU, calcium - 1468,5 ± 78,3 mg. Also, half of the pregnant women under the survey confirmed they intake fish oil. Multivitamin supplements including vitamin D of 400 IU were taken by 49 (81,7%) of pregnant women.Conclusions. Survey results show insufficient vitamin D dietary intakes, while there is a sufficient supply of calcium, mainly due to the consumption of dairy and meat products. Additional supplementation of vitamin D should be considered.

Prevalence of Vitamin D Deficiency among Geriatric Patients

Background: Vitamin D deficiency is recognized as a global public health problem. In India Vitamin D Deficiency is prevalent, a finding that is unexpected in a tropical country with abundant sunshine. This study evaluated prevalence of vitamin D deficiency among geriatric patients.Methods: The present study was a hospitalized based cross sectional study conducted among geriatric patients attending the ortho. OPD of CIMS, Lucknow. Those elderly (>60 yrs) consenting to participate were including in this study .Patients who were on vitamin D3 & calcium supply (6 month) were excluded. Results: In this study we have taken 200 sample size. Geriatric patients who were not on vitamin D and calcium supplements for last 6 months were included for the study. Out of 200 participants, only 27(13.5%) participants had normal vitamin D levels and 173 (86.5%) study participants had low vitamin D levels among them 112 (56%) participants had vitamin D deficiency, 61(30.5%) participants had vitamin D insufficiency. Conclusions: Present study confirmed that Vitamin D deficiency is a major public health problem among geriatric age group.

Adsorption of Copper in Soil and its Dependence on Physical and Chemical Properties

Soil samples (n = 11) were collected in the chernozem areas of the Czech Republic (the Central Europe) from the topsoil and used as representative samples. All sampling areas have been used for agricultural purposes (arable soil) and they were selected as typical representatives of agricultural soil. These samples represented the soil with same genesis (to reduction differencies between soil types) but with different soil properties (physical and chemical). Complete chemical and physical analyses were made for confirmation of copper adsorption on solid phase: we analysed the particle size distribution, content of oxidizable carbon (Cox), the cation exchange capacity (CEC), supply of exchange calcium, magnesium, sodium, phosphorus and potassium, soil reaction and the total supply of Fe, Al, Mn, Ca, Mg, K, P and N. The strongest simple correlation between analysed soil properties and copper concentration had content of available magnesium (r = 0.44) and available phosphorus (r = −0.51). In the case of multiple correlations (i. e. collective influence of multiple soil properties) had the strongest influence combination of clay, soil reaction, total content of phosphorus, available magnesium and available phosphorus. The main influence of phosphorus and magnesium is evident. We suppose that copper and phosphorus enter into specific complex. Influence of these five soil properties can explain 92.7 % (r = 0.927) changes in the content of copper changes in the experiment.

The Effects of Differences in Vegetation on Calcium Dynamics in Headwater Streams

Although organisms can alter dynamics of elements in ecosystems via physiological results, the effects of tree species on ecosystem nutrient dynamics are highly uncertain. A four-fold variation in the calcium concentrations of streams, soils and leaf litters were caused by the planting of Cryptomeria japonica in south-central Japan. In this study, we examined how the calcium dynamics were affected by the planting of C. japonica through strontium isotope analysis. We predicted the planting of C. japonica would result in the calcium concentration increasing because of the significant dissolution of calcium from bedrock. In a forest ecosystem, calcium is usually derived from precipitation and bedrock weathering, and their relative contributions can be estimated using a strontium isotope mixing model. Therefore, we collected stream water, litter, soil, precipitation and bedrock samples from 17 sites in catchments dominated by C. japonica plantation or evergreen broad-leaved forest; after collection, we analyzed the sample chemical compositions and strontium isotope ratios. The calcium concentrations in the stream water and the water-soluble calcium in the soil were significantly higher at sites dominated by C. japonica than at broad-leaved forest sites. Strontium isotope analysis indicated that there was more calcium from the bedrock present in stream water at sites dominated by C. japonica than in stream water at broad-leaved forest sites. Our results showed that watershed-scale dynamics of calcium and other cations can be altered by the type of vegetation in a catchment due to the effects of vegetation on the supply of calcium from bedrock.

Ca Distribution Pattern in Litchi Fruit and Pedicel and Impact of Ca Channel Inhibitor, La3.

Calcium (Ca) deficiency in fruit causes various physiological disorders leading to quality loss. However, disorders related to Ca deficiency are not simply caused by a shortage of calcium supply. Ca distribution is also an important relation. This study examined Ca distribution pattern in fruit and pedicel in litchi (Litchi chinensis Sonn.) and the influence of Ca channel inhibitor La3+ on fruit Ca uptake and distribution. In situ distribution of Ca in the phloem and xylem tissues of the pedicel was visualized by Ca mapping with X-ray microanalyzer. Ca2+ analogy Sr2+ was used to trace Ca2+ transport pathway to fruit as well as distribution pattern. The results showed Ca was more distributed in the pericarp, especially the distal part. Ca level in the bark/phloem was always significantly higher than in the xylem and increased with stem age, suggesting constant influx of Ca into the phloem from the xylem. La3+ increased the ratio of Ca in the xylem to that in the bark in the pedicel and significantly reduced Ca accumulation by 55.6% in fruit, suggesting influx of Ca into the symplast was involved in fruit Ca uptake. Sr2+ introduced from fruit stalk was found to be transported to fruit through the phloem as Sr was largely distributed in the phloem, and fruit stalk girdling significantly reduced Sr accumulation in the pericarp. Ca mapping across the pedicel revealed Ca-rich sites in the parenchyma cells in the phloem and along the cambium, where abundant Ca oxalate crystals were found. The results suggested extensive influx of Ca from xylem/apoplast pathway into the phloem/symplast pathway in the pedicel, which enables phloem/symplast pathway to contribute a considerable part to Ca uptake in litchi fruit.

Bromatological characteristics of Macrotyloma axillare as a function of combined supply of phosphorus and calcium

Bromatological characteristics of Macrotyloma axillare as a function of combined supply of phosphorus and calcium

Effects of rapeseed meal fiber content on phosphorus and calcium digestibility in growing pigs fed diets without or with microbial phytase

The optimization of dietary phosphorus (P) and calcium (Ca) supply requires a better understanding of the effect of dietary fiber content of co-products on the digestive utilization of minerals. This study was designed to evaluate the effects of dietary fiber content from 00-rapeseed meal (RSM) on P and Ca digestibility throughout the gastrointestinal tract in growing pigs fed diets without or with microbial phytase. In total, 48 castrated male pigs (initial BW=36.1±0.4 kg) were housed in metabolic crates for 29 days. After an 8-day adaptation period, pigs were allocated to one of the eight treatments. The impact of dietary fiber was modulated by adding whole RSM (wRSM), dehulled RSM (dRSM) or dRSM supplemented with 4.5% or 9.0% rapeseed hulls (dRSMh1 and dRSMh2). Diets contained 0 or 500 phytase unit of microbial phytase per kg. From day 14 to day 23, feces and urine were collected separately to determine apparent total tract digestibility (ATTD) and apparent retention (AR) of P and Ca. At the end of the experiment, femurs and digestive contents were sampled. No effect of variables of interest was observed on growth performance. Microbial phytase increased ATTD and AR of P (P<0.001) but the P equivalency with the wRSM diet was lower than expected. Moreover, stomach inorganic P (iP) solubility was improved by microbial phytase (P<0.001). The ATTD of Ca was not affected by microbial phytase which increased AR of Ca and femur characteristics (P<0.05). Ileal recovery of P was not affected by microbial phytase but cecal recovery was considerably reduced by microbial phytase (P<0.001). The decrease in digesta pH between the distal ileum and cecum (7.6 v. 5.9) enhanced the solubility of iP and may have improved its absorption, as supported by the negative relationship between soluble iP and pH (R2=0.40, P<0.001 without microbial phytase and R2=0.24, P=0.026 with microbial phytase). The inclusion of hulls improved the solubility of iP (P<0.05). In conclusion, dehulling does not largely increase nutrient digestibility although dRSM seems to improve the efficacy of microbial phytase in releasing phosphate in the stomach. Moreover, dietary fiber may affect solubilization process in the cecum which potentiates the effect of microbial phytase on P digestibility.

Effects of Insulin Resistance Induced by Dexamethasone on Bone Mass in Ovariectomized Rats

Glucocorticoids therapy is the most common cause of secondary iatrogenic osteoporosis.The bone loss occurs predominantly due to a decrease in bone formation, although increased bone resorption also occurs. Insulin resistance is the key pathology in type 2 diabetes negatively influence bone remodeling and leads to reduced bone strength. Loss of sex steroids, particularly oestradiol, as in ovariectomized rats,leads to increased skeletal remodeling over and above the age-related increment, together with excessive osteoclast activity. In this study, ovariectomy DEX group has highly significant increase in relative cortical resorptioncompared to ovaiectomy and sham DEX groups, also ovariectomy and DEX group has highly significant decrease in bone thickness compared to ovariectomy and sham DEX groups. The consequent increase in remodeling activation increases the overall resorption rate without a compensatory increase in formation, leading to rapid bone loss.This negative effect on bone which is due to the glucocorticoid excess is also mediated by indirect mechanisms such as the calcium malabsorption and hypercalciuria. In response to the enhanced supply of calcium from the skeleton, PTH secretion tends to be diminished, thereby reducing vitamin D [1,25(OH)2 cholecalciferol] concentration with a consequent reduction in calcium absorption.

Bone Mineral Density and Vitamin D Status in Children with Chronic Neurological Syndromes—Clinical Observations

Background: Some of the risk factors for osteoporosis population include: chronic immobilisation, insufficient dietary supply of calcium and vitamin D, decreased physical activity and long-term pharmacological treatment (glucocorticoids, anticonvulsant drugs). In disabled children and adolescents, the negative impact of these factors may cumulate to considerably impair the quality of life. Objectives: The aim of our study was to assess the vitamin D status and bone mineral density in children with chronic neurological syndromes. Material and Methods: A total of 34 children between 3 and 18 years of age were examined: 9 children with muscular dystrophy, 17 with cerebral palsy and 8 with lumbar myelomeningocele. All the subjects underwent the following assessments: measurement of the concentration of the hepatic metabolite of vitamin D and total body less head and/or lumbar spine densitometry by dual energy X-ray absorptiometry (DEXA). Low bone mass or low bone mineral density was diagnosed if the Z-score value was found to be equal to or below −2.0. Results: Indications for the above tests were chronic immobilisation or motor activity restriction, and—in 10/34 children—femoral or vertebral fracture. Vitamin D deficiency (81%). Low bone mass on densitometry was demonstrated in 27/34 and osteoporosis in 10/34 subjects (Z-score ≤ −2.0). Conclusion: Bone densitometry should be included in the standard of care for children with chronic neurological syndromes, and early detection of low bone mass should be an indication for treatment with calcium and vitamin D.

Eating habits and nutritional status of patients with affective disorders and schizophrenia.

The aim of the study was to assess the nutritional value of the food intake in the group of men and women suffering from recurrent affective disorders and schizophrenia, and also to determine the relation between selected nutritional parameters with anthropometric indices defining the nutritional status of the subjects. 219 persons participated in the study (61 patients with recurrent depressive disorders, 60 patients with schizophrenia and 98 healthy volunteers). A24-hour dietary recall was used in the quantitative assessment of the diet. Anthropometric and biochemical measurements as well as body composition analysis were used to assess the nutritional status. It was shown that women with depression and schizophrenia had a significantly higher content of both visceral adipose tissue and subcutaneous adipose tissue as compared with the control group. A diet with a higher content of energy from protein, a higher supply of calcium promoted a lower fat content in the bodies of women suffering from depression (no such relationship was observed in the group of men). In the group of patients with schizophrenia, a diet with a lower supply of energy promoted a lower BMI value, waist circumference, lower waist-hip ratio and a lower fat content in the body. An improper energy structure and an improper content of nutrients can, in the future, contribute to the development of many somatic diseases, thus leading to deterioration of life quality of subjects and preventing the maintenance of mental health.

Changes in bone turnover and calcium homeostasis during pregnancy and lactation in mammals: a meta-analysis.

Large amounts of calcium are required during pregnancy and lactation to support fetal and neonatal bone growth and calcification. An inadequate supply of calcium during these stages can lead to unsuccessful reproduction or impaired offspring fitness. During reproduction, female mammals undergo numerous physiological changes, including adaptations to allow an adequate supply of calcium. The lack of quantitative studies analysing these physiological changes from a comparative perspective limits our ability to explain and understand these adaptations. Herein, we present our meta-analysis of studies reporting changes in bone turnover and calcium homeostasis during pregnancy and lactation in 14 species of mammals. Our meta-analysis of 60 studies showed that all species have a similar pattern of physiological changes during pregnancy and lactation, which include: (1) decreased serum calcium concentrations; (2) bone tissue loss; (3) decreased serum calcitonin and parathyroid hormone concentrations; and (4) increased serum calcitriol concentration, regardless of changes in parathyroid hormone concentrations. In addition, we found a negative relationship between: (1) serum calcium concentrations and the number of teats; and (2) serum parathyroid hormone concentrations and litter mass.

Dietary Patterns in Toddlers with Excess Weight. the 2016 Pitnuts Study

IntroductionChildren’s appropriate dietary pattern determines their optimal development, reduces the risk of childhood diseases and the risk of diet-dependent diseases, including obesity in adulthood.AimTo analyze the dietary patterns of children with excess weight aged 1-3 years in comparison with the main components of the safe nutrition model including: the organization of meals (frequency of meals), selection of products (food intake), energy and nutritional value of children’s diets.Material and methodsThe study was carried out in 2016 on a representative nationwide sample of children aged 5-36 months (n=1059). The analysis of dietary patterns covered 173 with excess weight children aged 13-36 months (BMI-z-score >1 SD). Their nutritional status was evaluated based on BMI and its standardisation according to the WHO reference child growth standards for children aged 0-5 years (BMI z-score). The diets of children were assessed using 3-day dietary records. The dietary patterns of the children who were analysed were determined using the cluster analysis (k-means method), including 11 variables concerning average daily intake of main food group products (cow’s milk, junior formula, milk products, bread, groats and rice, cereals, cured meats, fats, sugar and sweets, fruits, nectars and juices).ResultsThree clusters of overweight and obese children with different dietary patterns were identified. The diet of children from the first cluster (n=58) was based primarily on junior formula and foods for infants and toddlers. This dietary pattern was defined as the “baby food diet”. The second cluster comprised 33 children whose diets were characterised by high consumption of cow’s milk and dairy products, as well as cereal products, including bread, groats, rice and breakfast cereals. This dietary pattern was defined the “milk and cereals diet”. The third cluster consisted of 82 children whose dietary pattern was characterised by high consumption of bread, cold meats and fats, sweets, juices and fruits (the “sandwich and sugar diet”). In all the clusters the average intake of vegetables and fruit by children with excess weight was significantly lower than the recommended amounts. The study showed too high intake of energy, protein, sodium, B vitamins and saccharose and an insufficient supply of calcium, fibre, vitamin D, vitamin E, LCPUFA, iodine and potassium in the children’s diet in reference to nutritional recommendations. Younger children with the “baby food diet” pattern, due to the contribution of enriched food, had a more balanced diet in relation to the model of safe nutrition (nutritional norms). Older children’s diets – in the third year of life, were characterized by a diversified choice of products that are a source of protein and carbohydrates (milk, breakfast cereals, meat, bread, cold meats, sugar from beverages, dairy desserts and juices).ConclusionThe identified dietary patterns of toddlers with excess weight differ from the safe nutrition model in terms of product selection and nutrient profile.

Absence of Calcitriol Causes Increased Lactational Bone Loss and Lower Milk Calcium but Does Not Impair Post-lactation Bone Recovery in Cyp27b1 Null Mice.

We hypothesized that adaptation to calcium supply demands of pregnancy and lactation do not require calcitriol. Adult Cyp27b1 null mice lack calcitriol and have hypocalcemia, hypophosphatemia, and rickets. We studied wild-type (WT) and null sister pairs raised on a calcium-, phosphorus-, and lactose-enriched "rescue" diet that prevents hypocalcemia and rickets. Bone mineral content (BMC) increased >30% in pregnant nulls, declined 30% during lactation, and increased 30% by 4 weeks post-weaning. WT showed less marked changes. Micro-CT revealed loss of trabecular bone and recovery in both genotypes. In lactating nulls, femoral cortical thickness declined >30%, whereas endocortical perimeter increased; both recovered to baseline after weaning; there were no such changes in WT. Histomorphometry revealed a profound increase in osteoid surface and thickness in lactating nulls, which recovered after weaning. By three-point bend test, nulls had a >50% decline in ultimate load to failure that recovered after weaning. Although nulls showed bone loss during lactation, their milk calcium content was 30% lower compared with WT. Serum parathyroid hormone (PTH) was markedly elevated in nulls at baseline, reduced substantially in pregnancy, but increased again during lactation and remained high post-weaning. In summary, pregnant Cyp27b1 nulls gained BMC with reduced secondary hyperparathyroidism, implying increased intestinal calcium delivery. Lactating nulls lost more bone mass and strength than WT, accompanied by increased osteoid, reduced milk calcium, and worsened secondary hyperparathyroidism. This implies suboptimal intestinal calcium absorption. Post-weaning, bone mass and strength recovered to baseline, whereas BMC exceeded baseline by 40%. In conclusion, calcitriol-independent mechanisms regulate intestinal calcium absorption and trabecular bone metabolism during pregnancy and post-weaning but not during lactation; calcitriol may protect cortical bone during lactation. © 2017 American Society for Bone and Mineral Research.

Calcium Bioavailability from Mineral Waters with Different Mineralization in Comparison to Milk and a Supplement

ABSTRACTObjective: The aim of the present study was to compare the bioavailability of calcium from 3 mineral waters with different concentrations of minerals with that of milk and a calcium supplement.Methods: A single-center, randomized controlled trial with a crossover design with 21 healthy men and women was conducted at the Institute of Food Science and Human Nutrition, Leibniz University Hannover. The participants consumed the 5 test products providing 300 mg of calcium each on 5 examination days with 1-week wash-out phases in between. Primary outcome variables were the area under the curve of serum calcium levels for 10-hour (AUC0–10h) and 24-hour urinary calcium excretion.Results: In all groups, no significant differences in the AUC0-10h of serum calcium levels as well as in the 24-hour urinary calcium excretion were observed. Likewise, mean changes in serum phosphate and urinary phosphate, as well as serum parathormone, showed no differences between the groups.Conclusion: Given an equivalent bioavailability of calcium in all test products, neither a high concentration of SO42− or of HCO3 influenced the bioavailability of calcium. Accordingly, the use of mineral water with high concentrations of calcium constitutes a calorie-free calcium source that can improve calcium supply.